Avalanch

It looks like a pump-powered sandfall, but I don't have any experience with those so I can't say much about how it works. I am guessing there is no dust because the sand was cleaned very thoroughly before being added and they probably left it running for a few days and did large water changes until there were no more fine particles left. I would also assume you need a moderately dense type of sand to make sure it flows downward instead of the tank turning into a sandstorm.